Steel Dragon Tools 185 8" Concrete Hole Boring Rig Wet & Dry Core Drill with 2" 3" 4" Wet Laser Welded Diamond Concrete Bits Steel Dragon Tools 185 8" Concrete Hole Boring Rig Steel Dragon Tools CB-051 2 Wet Laser Welded Diamond Concrete Bit Steel Dragon Tools CB-076 3 Wet Laser Welded Diamond Concrete Bit Steel Dragon Tools CB-102 4 Wet Laser Welded Diamond Concrete Bit Powerful 3500W Induction 115V 60Hz 15 Amp high-speed series motor